Of the several groups of Streptococci, group A streptococcus (S. pyogenes) is primarily responsible for causing pathological conditions in humans, such as B-hemolytic pneumonia, scarlet fever, rheumatic fever, cardiac sequelae, glomerulonephritis, septic sore throat, and puerperal sepsis. Other groups of Streptococci are wholly innocuous and normally exist, for example, in the throat. Because of the serious nature of infections potentially caused by Streptococcus A, it is important to diagnose its presence in an early stage of infection so that an appropriate course of treatment may be selected. Streptococci may be cultured conventionally in suitable media; however, identifying Streptococci by type is not a simple task. Streptococci A-selective culture media are less than perfect in that they are not fully selective, i.e., they do not eliminate all other types of Streptococci while allowing Streptococcus A to grow. Importantly, culturing techniques for identifying Streptococci A generally require an incubation time of 18 hours, and frequently as long as 48 hours, to ascertain the presence of Streptococcus A. Such lengthy tests delay a fully informed judgment as to the best course of disease treatment. The desirability of a reliable, simple and quick test for Streptococcus A is clearly indicated.